1. Field of the Invention
This invention relates to an exhaust gas conditioning device, and more particularly, to a conditioning device for cooling hot exhaust gas by forming a hot exhaust gas-liquid mixture and thereafter separating the liquid from the cooled exhaust gas by centrifugal action.
2. Description of the Prior Art
It is well known that internal combustion engines normally discharge hot exhaust gas containing particulates to atmosphere. The discharge of hot exhaust gas containing particulates from vehicles propelled by internal combustion engines and used in underground mining environments is particularly hazardous to mining personnel working around these vehicles. For example, mining pesonnel could be injured if the hot exhaust gas ignites any combustible elements present in the mine, or be burned by the hot exhaust gas itself. In addition, the hot exhaust gas contains particulates which are unsafe for human inhalation.
In an attempt to reduce the temperature of the hot exhaust gas discharged by internal combustion engines used on underground mining vehicles and remove particulates suspended in the exhaust gas, various exhaust gas conditioners have been utilized.
U.S. Pat. No. 3,316,693 discloses an exhaust gas treating device which includes a perforated flame tube positioned within the treating device tank for receiving exhaust gas from a diesel engine. The flame tube is perforated to reduce back pressure losses to the engine. The exhaust gas is passed from the flame tube into a cylindrical expansion chamber positioned around the flame tube to expand the exhaust gas. After expansion, the exhaust gas enters a vertical tube which extends into a scrubbing liquid in the tank. The exhaust gas is discharged through the vertical tube into the liquid and passes upwardly through the scrubber liquid after striking a protector plate positioned on the bottom of the exhaust gas tank. The mixture of exhaust gas and liquid then follows a generally upward path and impinges upon helixical veins positioned on the outside of the vertical flow tube.
U.S. Pat. No. 3,485,015 discloses an exhaust gas scrubber which includes a housing containing a plurality of chambers. An inlet pipe introduces exhaust gas into at least one of the chambers. The exhaust gas passes through several chambers containing a fume scrubbing liquid, and after scrubbing, the gases are discharged through an outlet pipe. The inlet pipe divides the exhaust gas into a plurality of paths each containing separate fume scrubbing chambers. After the exhaust gas is separated and passed through the plurality of chambers, the gas is recombined at a location adjacent the outlet of the scrubber.
U.S. Pat. No. 3,561,194 discloses an exhaust gas conditioner wherein exhaust gases introduced into the conditioner are passed through water-filled chambers to be cooled and scrubbed by contact with the water.
U.S. Pat. No. 3,886,738 discloses a diesel engine for use in mines in which the exhaust system for the engine includes a liquid cooled exhaust manifold, apparatus for injecting a water spray into the exhaust gas flowing from the manifold to cool the exhaust gas, and a scrubber which functions as an exhaust arrester and an exhaust gas diluter to remove contaminants from the exhaust gas.
U.S. Pat. No. 3,967,941 discloses an exhaust gas liquid contactor for removing particulate matter from hot exhaust gas in which water vapor is added to the exhaust gas and thereafter the exhaust gas is cooled to cause condensation of the water vapor in the exhaust gas into water droplets surrounding the particulate matter. The exhaust gas-water droplet mixture is passed through a filter to remove the water droplets from the exhaust gas and thereby simultaneously remove the particulates from the exhaust gas.
U.S. Pat. No. 3,976,456 discloses an exhaust gas scrubber which includes an enclosure partially filled with a liquid having an inlet above the liquid level. A tube positioned in the enclosure is connected to the enclosure inlet and extends downwardly below the water level, then changes direction to extend upwardly with constantly increasing cross-section and with at least some portion of the tube in curvature to an open end within the enclosure and above the liquid level. Orifices in the submerged portion of the tube emit water droplets which are drawn into and mixed with the gas in proportion to the amount of combustion exhaust from the engine. As the gas-water mixture passes through the tube, the water droplets and particulate matter are separated from the gas by a combination of centrifugal force and their own weight as the gas stream is slowed down within the tube.
U.S. Pat. No. 4,300,924 discloses an exhaust gas scrubber which includes a closed tank partially filled with water and a core assembly positioned within the tank. The assembly includes a vertical cylindrical mixing tube open at its opposite ends and extending above and below the water level, an upwardly open cylindrical deflector cup at the bottom of the tank with its opening concentrically spaced within the lower end of the mixing tube, and a downwardly opening cylindrical deflector hood concentrically receivng the upper end of the mixing tube. Exhaust gases are introduced into the tank through a gas inlet tube which extends downwardly concentrically through the deflector hood and mixing tube. The gas inlet tube includes an open cover end. The gases flowing through the inlet tube discharge into the deflector cup and are deflected upwardly by the cup to pass through the annular opening between the gas inlet tube and the mixing tube. As the gases enter this annular opening they aspirate water droplets. The water droplets and gases intermix as the gases rise through the annular opening, and the mixture is deflected downwardly by the deflector hood towards the pool of water. The water droplets return to the pool while the gases are expelled from the tank through an opening in the tank.
While it has been suggested by the prior art devices to clean and cool hot exhaust gases by passing the exhaust gases through a pool of water or entraining water droplets in a hot exhaust gas flow, there is a need for an improved scrubber-exhaust gas conditioner of small enough size to enable direct connection with an internal combustion engine manifold which efficiently cools the hot exhaust gas to provide a safe working environment for mine personnel. The improved scrubber-exhaust gas conditioner must be capable of achieving good contact and mixing of the exhaust gas and liquid within the conditioner. In addition, the scrubber-exhaust gas conditioner must be capable of achieving a high degree of recovery of the liquid after the exhaust gas is cooled to minimize liquid usage. The scrubber-exhaust gas conditioner must have a simple construction to reduce manufacturing and replacement costs and facilitate inspection of the conditioner components.